Post-mix beverage dispensing systems provide a convenient and efficient means for dispensing carbonated beverages to consumers. Such systems produce carbonated water, and mix flavored syrups with the carbonated water in desired ratios at a dispensing head or bar gun. Where such systems can be used, post-mixed beverages are highly cost-effective compared to more expensive pre-packaged carbonated beverages such as canned or bottled soft drinks.
Presently, commercial airlines typically serve prepackaged beverages to their passengers. Prepackaged beverages such as canned beverages are stored at room temperature in a portable cart that is sufficiently narrow to pass down the aisles of most commercial aircraft. As passengers request carbonated beverages, flight attendants remove the selected canned beverages from the portable cart, and pour the beverages over ice in a glass or cup. This process is time-consuming, and can be difficult or impossible under turbulent flight conditions. On short flights, at least some passengers often are unable to obtain a beverage due to the time required to dispense canned beverages to previously served passengers. In addition, the cost per serving of canned beverages is considerably higher than the cost per serving cost post-mixed carbonated beverages. Serving pre-packaged beverages also generates considerable waste such as empty beverage cans that must be handled, temporarily stored, and discarded. In addition, pre-packaged carbonated beverages have a limited shelf life.
The challenges associated with producing compact and portable post-mix beverage dispensing systems are numerous. Such systems must operate without external sources of water and electric power. In addition, such systems must be sufficiently compact to permit their use in limited spaces such as the narrow confines of airplanes. Because such systems necessarily include stored high pressure carbon dioxide gas, the systems also must comply with stringent government safety regulations governing the packaging and transportation of high pressure gas containers. Furthermore, the makers of the most popular carbonated beverages (e.g. Coke ® and Pepsi ®, require their products to be consistently dispensed according to exacting product standards. One such requirement is that the dispensed beverages have a commercially acceptable level of carbonation of about 3 percent to about 4 percent.
Others have attempted to produce compact and portable post-mix beverage dispensing systems with limited success. For example, U.S. Pat. Nos. 5,411,179 and 5,553,749 to Oyler et al. describe self-contained beverage dispensing systems that use a single low-pressure motorless carbonator to carbonate flat water to produce soda for use in post-mixing and dispensing carbonated beverages. Unfortunately, such low-pressure motorless carbonators produce soda having only about 2.5 percent carbonation, which is well below a commercially acceptable level of carbonation and/or product standards dictated by makers of Coke ® and Pepsi®. Others have tried to address this problem by developing portable beverage dispensers that include a single high-pressure motorless carbonator. The term “high pressure motorless carbonator” as used herein refers to a motorless carbonator that operates at an internal pressure of at least about 100 psi. For example, U.S. Pat. No. 6,021,922, U.S. Pat No. 6,234,349, and U.S. Pat. No. 6,253,960 to Bilskie et al. describe self-contained high-pressure beverage dispensing systems that include a single motorless carbonator that operates at a gas pressure of between 90-110 psi. Unfortunately, these systems also do not provide a highly portable and compact beverage dispensing system that produces soda that consistently meets commercially acceptable levels of carbonation and complies with applicable federal safety regulations for use on commercial aircraft.
Accordingly, there is a need for an effective, compact, and highly portable beverage dispensing system that operates without external sources of water and electric power. In addition, there is a need for such a system that is sufficiently compact to permit its use in limited spaces such as the narrow aisles of airplanes and passenger railcars. Such a system also must comply with applicable government safety regulations, and must consistently supply a commercially acceptable level of carbonation.